1. Field of the Invention
The present invention relates to a sheet feeding device.
2. Description of the Related Art
Commonly-used image forming apparatuses, such as printer, includes a sheet feeding device that transports, for example, a print medium to an image reading mechanism or to an image forming mechanism. The sheet feeding device has a standby state and a feeding state. In the standby state, a plurality of print media to be read can be set in a shooter that holds the print media. In the feeding state, as a result of a pick roller and one of the print media coming into contact, only a print medium in contact with the pick roller is transported in a transport direction. When the pick roller and a print medium come into contact while the sheet feeding device is in the standby state, an edge of the print medium may become deformed. As a result, sheet-feeding performance may degrade. When the pick roller and a print medium come into contact while the sheet feeding device is in the standby state, positioning of print media in the transport direction, performed when the print media are set in the shooter, becomes unclear, resulting in inconvenience to users.
Japanese Patent Application Laid-open No. S61-064630 discloses a conventional sheet feeding device in which a pick roller and print media to be read are separated while the sheet feeding device is in standby state and the positioning in the transport direction is clarified. The sheet feeding device includes a flap-integrated setting guide. The flap-integrated setting guide includes a flap section that comes into contact with an edge of a print medium to be read to separate the print medium and a setting roller when the sheet feeding device is in feeding state. The flap-integrated setting guide prohibits the movement of the print medium in the transport direction by coming into contact with the edge of the print medium when the sheet feeding device is in standby state.
However, when the sheet feeding device transitions from standby state to feeding state, the prohibited movement of the edge of the print medium cannot be permitted before the pick roller and the print medium come into contact. This may cause deformation of the print medium transported by the pick roller immediately after transition from standby state to feeding state.
Japanese Patent Application Laid-open No. 2004-269231 discloses another conventional sheet feeding device including a flap and a setting guide are provided. The flap prohibits the movement of a print medium to be read in the transport direction by coming into contact with an edge of the print medium. The setting guide separates the print medium and the setting roller by coming into contact with the print medium. The flap and the setting guide can move using different driving sources, i.e., the flap and the setting guide can move separately. Therefore, the movement of the print medium in the transport direction, prohibited by the flap, can be permitted before the setting guide allows the pick roller and the print medium to come into contact. Thus, the deformation of a print medium, which is moved in the transport direction by the pick roller immediately after transition from standby state to feeding state, can be reduced.
However, the conventional sheet feeding device needs two drive sources to move the flap and the setting guide to allow the movement of a print medium in the transport direction, prohibited by the flap, before the setting guide allows the pick roller and the print medium to come into contact.